It is well known to provide a gear shift having a gear lever for effecting a manual gear change of a multi-speed transmission. Examples of such gear shifts are known from, for example U.S. Pat. Nos. 4,543,842, 5,560,253; European Patent Publication 1267240 and US Patent Publication 2015/0198238.
Such gear shifts include a spring based biasing means to position the gear lever into a preferred neutral position.
FIGS. 1 and 2 show in a diagrammatic manner one example of such a spring biased neutral gear shift.
In FIG. 1 a plan view is shown in which it can be seen that there are four forward gears arranged in an “H” pattern. First and second gear selected or engaged positions f1 and f2 are arranged so as to lie in a first plane and third and fourth gear selected positions f3 and f4 are arranged to lie in a second plane offset from the first plane. The first and second planes are arranged to extend in a Fore-Aft direction of a motor vehicle to which the gear shift is fitted.
A transverse neutral plane joins the first and second planes and in this case is arranged at right angle to the first and second planes and extends in a Left-Right transverse direction of the motor vehicle.
A reverse gear “R” is selectable by movement of the gear lever into a gate lying on a sub-plane arranged parallel to but offset from the first plane.
In FIG. 2 a gear lever 1 is shown at 1a positioned in the transverse neutral plane in a neutral position so as to align the gear lever 1 with the second plane and is shown in dotted outline at 1b in the transverse plane aligned with the first plane.
Conventionally the gear lever 1 is biased so as to align it with the second plane by one or more springs indicated diagrammatically by the coil spring 2 acting between a fixed abutment 5 and an arm 3 extending from a pivot member 4 from which the gear lever 1 extends. The pivot member 4 allows the gear lever 1 to move in a fore-aft direction as well as a left-right direction so as to permit the various gears to be engaged.
When the gear lever 1 is positioned in the transverse neutral plane with no external load applied it will automatically adopt the position la shown in FIG. 2 and “N” in FIG. 1 due to the effect of the coil spring which urges the arm 3 into abutment with a stop 6. Therefore when changing between third and fourth gears no left or right load needs to be applied by a driver of the vehicle.
However, when it is required to move from the second plane to the first plane such as, for example, when changing from third gear to second gear then the driver is required to apply a force to the gear lever against the action of the spring 2 to traverse along the transverse neutral plane in order to reach the first plane. A further stop 7 is provided to limit the leftward transverse motion of the gear lever 1 so as to provide good alignment of the gear lever 1 with the first plane. It will be appreciated that the stop 7 is moveable to as to permit reverse gear to the selected.
Although such an arrangement is useable when only four forward gear ratios are available for selection it is less satisfactory when more than four ratios are provided. If, for example six forward gear ratios are selectable then some drivers find it difficult to select the correct ratio if a fixed neutral position is used irrespective of the plane with which the gear lever is biased to align with when in the transverse neutral plane.